Beyond the Obvious: Why 2026 demands a rethink of portfolio diversification

Geopolitics has become a much more significant driver of markets. A busy election calendar, including Brazil (4th October), Israel (27th October) and the US midterm elections (3rd November), could create policy uncertainty that affects regions, sectors and investment styles.

At the same time, supply chains continue to evolve. Trends such as reshoring and friend-shoring are changing trade flows and production costs. Research from the IMF and ECB suggests that increasing trade fragmentation could slow growth and affect the availability and pricing of critical inputs in sectors such as semiconductors and clean technology.

Meanwhile, the Middle East remains an important risk channel. Disruptions to Red Sea shipping routes during 2024-25, alongside ongoing tensions around the Strait of Hormuz, have periodically pushed up energy, freight and insurance costs. These pressures can quickly feed through to inflation expectations and market volatility.

For investors, these are increasingly structural features of the investment landscape rather than isolated considerations. Portfolios may therefore need multiple sources of diversification rather than relying on a single defensive asset.

What you see isn’t always what you get. Many portfolios that appear diversified across funds and asset classes still have significant exposure to a small number of companies, factors or regions.

For example, the top ten stocks in the S&P 500 recently represented around 37-38% of the index's market value, close to multi-decade highs. At the same time, around 64% of the MSCI All Country World Index is invested in the US, while Japan, the second-largest country allocation, accounts for only around 5%. As a result, just ten US companies represent almost a quarter of global equity market exposure.

Source: Life Investment Office, Aladdin data, 31/07/2026. UK equity is represented by the FTSE All-Share index, European ex UK Equity is represented by the FTSE Europe ex UK index, US Equity is represented by the S&P 500 index, Japan Equity is represented by the Topix index and Emerging Markets Equity is represented by the MSCI Emerging Markets index. Past performance is not a reliable indicator of future performance. 

Where concentration can hide in Model Portfolio Services: 

• Factor crowding: managers with similar growth-oriented approaches may struggle at the same time during market downturns.
• Regional bias: global equity allocations often carry substantial US exposure.
• Bond benchmarks: passive bond indices allocate more to the biggest borrowers, increasing exposure to heavily indebted issuers and US interest-rate risk.
   

Diversification failures rarely occur because investors own too few holdings. More often, they arise because seemingly different investments behave in similar ways when markets become stressed.

Political and economic developments are increasingly shaping portfolio outcomes. Election results can influence taxation, spending plans, tariffs and industrial policy, with knock-on effects for company earnings and valuations.

Trade and energy routes remain vulnerable to disruption, while companies continue to adapt supply chains in response to geopolitical concerns. Research from the IMF and ECB suggests even partial economic fragmentation may increase costs, reduce efficiency and create new sources of volatility.

These forces can affect growth, inflation and market leadership across regions, making it increasingly important to avoid portfolios reliant on a single investment narrative.

Traditional portfolio construction has long relied on equities and bonds offsetting each other's risks. However, this relationship weakened significantly after 2021 as inflation and interest-rate uncertainty increased.

When inflation becomes a dominant concern, shares and bonds can fall together, reducing the diversification benefits investors have historically expected. The experience of 2022 highlighted this risk, with both asset classes suffering significant losses at the same time. While a portfolio of 60% in global equities and 40% in global bonds rebounded in subsequent years, 2022 was widely regarded as one of the most challenging years for traditional multi-asset investors since the 1930s.

The lesson remains clear: correlations can change. Investors may therefore benefit from broader sources of diversification rather than relying solely on equities and bonds to provide portfolio resilience.

In today's environment, diversification means more than simply spreading money across asset classes.

Equities: Broaden exposure beyond US mega-cap leaders through regional diversification and a mix of investment styles, including quality, value and smaller companies.

Fixed Income: Take a more granular approach by combining short-dated bonds, sovereign debt, investment-grade and high-yield credit, inflation-linked securities and selective emerging market debt.

Alternatives: Assets such as infrastructure, real assets, commodities, gold and certain alternative strategies can provide additional diversification when equity and bond correlations become less reliable.

The common theme is simple: resilience comes from having more independent return drivers rather than more of the same exposures.

In our view, diversification in 2026 needs to be broader, deeper and more intentional. That means looking beyond headline asset allocations and understanding how portfolio exposures interact during different market environments.

By reducing hidden concentration, broadening sources of return and incorporating a wider range of diversifiers, investors may be better positioned to navigate changing market conditions and evolving geopolitical risks.

If you found this piece useful…

Look out for our next webinar where we will examine the current tale of two forces: inflation pressures vs the AI growth story. Registration details to follow shortly. 

Past performance is not a reliable indicator of future performance. The value of an investment can go down as well as up and your client may get back less than they’ve paid in.